Usefulness of percutaneous microwave ablation for large non-small cell lung cancer: A preliminary report.

The role of microwave ablation (MWA) in patients with non-small cell lung cancer (NSCLC) remains ill-defined. This retrospective study evaluated the oncological outcomes of CT-guided MWA in patients with large NSCLC. Kaplan-Meier analysis was used to evaluate overall survival (OS) and cancer-specific survival (CSS). The log-rank test was used to compare survival between patients with an NSCLC size greater or smaller than 4 cm. The likelihood of local tumor progression (LTP) was analyzed using a multivariable regression model. A total of 53 patients with 65 tumors were analyzed. The mean tumor size was 5.0±1.8 cm. At the 1-month CT scan, complete tumor ablation was observed in 44.6% of cases. In 18.5% of cases a redo-MWA session was carried out, while in 4.6%, a third MWA was necessary to obtain complete tumor necrosis. The mean follow-up was 28.1±20.6 months with a median duration of 21.5 months. The 1-year, 2-year, 3-year and 5-year OS rates were 78.2, 48.3, 34.8 and 18.3%, respectively. The median CSS was 25 months (95% CI 15.5-34.5). The 1-year, 2-year, 3-year and 5-year CSS rates were 84.3, 53.7, 42.1 and 30.0%, respectively. OS in patients with tumor size ≥4 cm was significantly lower when compared with those having smaller tumors (P=0.03). LTP was observed in 19 patients (35.8%). Incomplete tumor ablation [odds ratio (OR) 6.57; P<0.05] and tumor size ≥4 cm (OR 0.18; P<0.05) were significant independent predictors of LTP. In conclusion, CT-guided MWA may represent a useful tool in the multimodality treatment of patients with large advanced NSCLC.

Percutaneous Microwave Ablation Under CT Guidance for Hepatocellular Carcinoma: a Single Institutional Experience.

BACKGROUND: Microwave ablation (MWA) is an emerging treatment for treatment of patients with hepatocellular carcinoma (HCC) not amenable of surgical resection. PATIENTS AND METHODS: We searched for patients diagnosed as having small-, medium-, and large HCCs treated with MWA under CT guidance between 2010 and 2014. The main outcomes of interest were rates of complete ablation, complications, and overall survival. Rates of complete ablation were compared with Chi-square test, and estimated survival rates were calculated by means of Kaplan-Meier method. RESULTS: Thirty-two patients with 45 HCC nodules received MWA. Seventeen (37.8%) nodules were <3 cm (small), 15 (33.3%) between 3 and 5 cm (medium), and 13 (28.9%) > 5 cm (large). Complete ablation was obtained in 94.1% of small tumors, 80% of medium tumors, and 53.8% of large tumors (p = 0.03). Two patients had HCC located in risk area (paracardiac position). Minor complications occurred after seven procedures (15.5%). Estimated median survival was 37 months (95% confidence interval 11.97-62.02). One-year OS was 82.7%, 2-year survival 68.9%, and 3-year survival 55.2%. CONCLUSION: MWA is a versatile ablative method that can be applied in HCC at various stages, and also in lesions located in risk areas.

CT-guided percutaneous screw fixation plus cementoplasty in the treatment of painful bone metastases with fractures or a high risk of pathological fracture.

OBJECTIVE: To evaluate the feasibility and effectiveness of computed tomography (CT)-guided percutaneous screw fixation plus cementoplasty (PSFPC), for either treatment of painful metastatic fractures or prevention of pathological fractures, in patients who are not candidates for surgical stabilization. MATERIALS AND METHODS: Twenty-seven patients with 34 metastatic bone lesions underwent CT-guided PSFPC. Bone metastases were located in the vertebral column, femur, and pelvis. The primary end point was the evaluation of feasibility and complications of the procedure, in addition to the length of hospital stay. Pain severity was estimated before treatment and 1 and 6 months after the procedure using the visual analog scale (VAS). Functional outcome was assessed by improved patient walking ability. RESULTS: All sessions were completed and well tolerated. There were no complications related to either incorrect positioning of the screws during bone fixation or leakage of cement. All patients were able to walk within 6 h after the procedure and the average length of hospital stay was 2 days. The mean VAS score decreased from 7.1 (range, 4-9) before treatment to 1.6 (range, 0-6), 1 month after treatment, and to 1.4 (range 0-6) 6 months after treatment. Neither loosening of the screws nor additional bone fractures occurred during a median follow-up of 6 months. CONCLUSIONS: Our results suggest that PSFPC might be a safe and effective procedure that allows the stabilization of the fracture and the prevention of pathological fractures with significant pain relief and good recovery of walking ability, although further studies are required to confirm this preliminary experience.

Combined Microwave Ablation and Cementoplasty in Patients with Painful Bone Metastases at High Risk of Fracture.

PURPOSE: To retrospectively evaluate the effectiveness of computed tomography-guided percutaneous microwave ablation (MWA) and cementoplasty in patients with painful bone metastases at high risk of fracture. MATERIALS AND METHODS: Thirty-five patients with 37 metastatic bone lesions underwent computed tomography-guided MWA combined with cementoplasty (polymethylmethacrylate injection). Vertebrae, femur, and acetabulum were the intervention sites and the primary end point was pain relief. Pain severity was estimated by visual analog scale (VAS) before treatment; 1 week post-treatment; and 1, 6, and 12 months post-treatment. Functional outcome was assessed by improved patient walking ability. Radiological evaluation was performed at baseline and 3 and 12 months post-procedure. RESULTS: In all patients, pain reduction occurred from the first week after treatment. The mean reduction in the VAS score was 84, 90, 90 % at week 1, month 1, and month 6, respectively. Improved walking ability occurred in 100 and 98 % of cases at the 1- and 6-month functional outcome evaluations, respectively. At the 1-year evaluation, 25 patients were alive, and 10 patients (28 %) had died because of widespread disease. The mean reduction in the VAS score and improvement in surviving patients' walking ability were 90 and 100 %, respectively. No patients showed evidence of local tumor recurrence or progression and pathological fracture in the treated sites. CONCLUSION: Our results suggest that MWA combined with osteoplasty is safe and effective when treating painful bone metastases at high risk of fracture. The number of surviving patients at the 1-year evaluation confirms the need for an effective and long-lasting treatment.

Computed Tomography-Guided Cryoablation of Local Recurrence after Primary Resection of Pancreatic Adenocarcinoma.

The optimal management of local recurrences after primary resection of pancreatic cancer still remains to be clarified. A 58-year-old woman developed an isolated recurrence of pancreatic cancer six year after distal pancreatectomy. Re-resection was attempted but the lesion was deemed unresectable at surgery. Then chemotherapy was administrated without obtaining a reduction of the tumor size nor an improvement of the patient's symptoms. Thus the patient underwent percutaneous cryoablation under computed tomography (CT)-guidance obtaining tumor necrosis and a significant improvement in the quality of life. A CT scan one month later showed a stable lesion with no contrast enhancement. While the use of percutaneous cryoblation has widened its applications in patients with unresectable pancreatic cancer, it has never been described for the treatment of local pancreatic cancer recurrence after primary resection. Percutaneous cryoablation deserves further studies in the multimodality treatment of local recurrence after primary pancreatic surgery.

Breast cryoablation in patients with bone metastatic breast cancer.

PURPOSE: To assess retrospectively the safety and feasibility of palliative breast cryoablation to treat primary breast tumors in patients with stage IV breast cancer. MATERIALS AND METHODS: In 17 female patients (mean age ± SD, 59 y ± 13; range, 37-81 y) with 22 bone metastatic ductal invasive breast lesions (2.5 cm × 1.6 cm ± 1.4 × 1.1; range, 1.0 cm × 0.5 cm to 6.7 cm × 5.5 cm), 19 computed tomography (CT)-guided percutaneous cryoablation sessions were performed for treatment of primary breast tumors. All patients had radiologic evidence (contrast-enhanced CT or magnetic resonance imaging) of persistence or progression of the primary breast cancer despite systemic therapy. The radiologic outcome was evaluated with a mean follow-up period of 13 months (range, 3-31 mo). Treatment of skeletal metastases was unnecessary during the follow-up period. RESULTS: All of the cryoablation sessions were completed and well tolerated. Complete regression of the disease was achieved in 15 (88%) patients 2 months after the cryoablation. Two (12%) patients underwent a second cryoablation treatment because of a minimal persistence of viable tumor (residual disease). No relapse of primary tumors was observed on breast imaging during the follow-up period. One patient (6%) developed a new lesion localized to the contralateral breast. CONCLUSIONS: These data suggest that palliative cryoablation of primary advanced breast cancer is a well-tolerated, feasible, and effective treatment option. Given the palliative effects of breast cryoablation demonstrated in this series, larger studies replicating these results are warranted.

Painful pelvic recurrence of rectal cancer: percutaneous radiofrequency ablation treatment.

PURPOSE: To retrospectively evaluate the feasibility and efficacy of computed tomography (CT)-guided radiofrequency thermal ablation (RFA) in reducing the pain in patients with painful pelvic recurrence of rectal cancer ineligible for surgical resection. MATERIAL AND METHODS: Twelve consecutive patients (10 men and 2 women; mean age 67 ± 10 years) with painful pelvic recurrence of rectal cancer underwent CT-guided RFA treatments under conscious sedation. At baseline, in all patients pelvic-sacral pain was classified as severe by Visual Analog Scale (VAS; VAS score ≥75 mm). The tumor density and carcinoembryionic antigen (CEA) serum level averages were 46 ± 7 HU and 15.7 ± 9.3 ng/mL, respectively. Clinical outcome was evaluated by VAS with a mean follow-up period of 23 months. RESULTS: All RFA sessions were completed and well tolerated. Morbidity consisted of recto-vesical fistula (8 %) and rectal abscess (8 %). 1 month after RFA procedure, complete lack of enhancement was obtained in 7 cases (58 %). A significant difference in HU and CEA serum level averages between baseline and 1 month post-RFA was revealed (p < 0.000 and p < 0.002, respectively). A significant reduction in pain was obtained: VAS score was significantly different between baseline and the clinical evaluations at week 1 and month 3, 6, 12, and 22) (p < 0.000). At the end of follow-up, 11 patients (92 %) were symptom free. CONCLUSIONS: CT-guided RFA of painful pelvic recurrence of rectal cancer can be considered as a feasible and effective treatment for reducing the pain in selected cases.

CT-guided thin needles percutaneous cryoablation (PCA) in patients with primary and secondary lung tumors: a preliminary experience.

PURPOSE: To report the data of our initial experience with CT-guided thin cryoprobes for percutaneous cryoablation (PCA) in patients with primary and secondary pulmonary tumors. MATERIAL AND METHODS: CT-guided thin needles PCA was performed on 34 lung masses (11 NSCLC=32%; 23 secondary lung malignancies=68%) in 32 consecutive patients (24 men and 8 women; mean age 67 ± 10 years) not suitable for surgical resection. Lung masses were treated using two types of cryoprobes: IceRod and IceSeed able to obtain different size of iceball. The number of probes used ranged from 1 to 5 depending on the size of the tumor. After insertion of the cryoprobes into the lesion, the PCA were performed with two 2 (91%) or 3 (9%) cycles each of 12 min of freezing followed by a 4 min active thawing phase and a 4 min passive thawing phase for each one for all treatments. RESULTS: All cryoablation sessions were successfully completed. All primary and metastatic lung tumors were ablated. No procedure-related deaths occurred. Morbidity consisted of 21% (7 of 34) pneumothorax and 3% (1 of 34) cases asymptomatic small pulmonary hemorrhage, respectively, all of CTCAE grade 1 (Common Terminology Criteria for Adverse Events). Low density of entire lesion, central necrosis and solid mass appearance were identify in 21 (62%), 7 (21%) and 6 (17%) of cryoablated tumors, respectively. No lymphadenopathy developed in the region of treated lesions. Technical success (complete lack of enhancement) was achieved in 82%, 97% and 91% of treated lesions at 1-, 3- and 6-months CT follow-up scan, respectively (p<.000). Comparing the tumor longest diameter between the baseline and at 6 month CT images, technical success was revealed in 92% cases (p<.000). CONCLUSION: Our preliminary experience suggests that PCA is a feasible treatment option. Well-designed clinical trials with a larger patient population are necessary to further investigate the long-term results and prognostic factors.

Treatment of bone metastases with microwave thermal ablation.

PURPOSE: To retrospectively evaluate the feasibility, safety, and effectiveness of computed tomography (CT)-guided percutaneous microwave ablation (MWA) in patients with bone metastases. MATERIALS AND METHODS: Twenty-one patients with metastatic bone lesions were treated in 18 MWA sessions. In patients whose lesions contained fractures, or who had a high risk for fracture (48%; n = 10), MWA was followed by cementoplasty with polymethylmethacrylate injection. The positioning of the MWA antenna into the tumor was guided by CT. Treatments were performed under conscious sedation. All patients underwent clinical (self-reported Brief Pain Inventory [BPI]; scale from 0 to 10) and radiologic evaluation at baseline and 1 month after the procedure. The reported results are data from baseline to a follow-up period of 3 months. RESULTS: There were no complications. A reduction of pain and improvement in quality of life was observed in all patients as measured by BPI score. On average, the mean BPI score during the 3-month follow-up period was reduced by 92% (41%-100%). Thirteen of 18 patients (72%) were symptom-free, four patients (22%) were still symptomatic but with 85% lower average BPI scores (41%-95%), and one patient (6%) experienced a recurrence of symptoms. CONCLUSIONS: Preliminary results suggest that MWA of bone metastases is a well tolerated, safe, and effective procedure. However, its efficacy still remains to be determined by medium- and long-term studies.

Microvascular function is selectively impaired in patients with hypertrophic cardiomyopathy and sarcomere myofilament gene mutations.

OBJECTIVES: The purpose of this study was to assess myocardial blood flow (MBF) using positron emission tomography in patients with hypertrophic cardiomyopathy (HCM) according to genetic status. BACKGROUND: Coronary microvascular dysfunction is an important feature of HCM, associated with ventricular remodeling and heart failure. We recently demonstrated the increased prevalence of systolic dysfunction in patients with HCM with sarcomere myofilament gene mutations and postulated an association between genetic status and coronary microvascular dysfunction. METHODS: Maximum MBF (intravenous dipyridamole, 0.56 mg/kg; Dip-MBF) was measured using (13)N-labeled ammonia in 61 patients with HCM (age 38 ± 14 years), genotyped by automatic DNA sequencing of 8 myofilament-encoding genes (myosin-binding protein C, beta-myosin heavy chain, regulatory and essential light chains, troponin T, troponin I, troponin C, alpha-tropomyosin, and alpha-actin). In 35 patients, cardiac magnetic resonance imaging was performed. RESULTS: Fifty-three mutations were identified in 42 of the 61 patients (genotype positive; 69%). Despite similar clinical profiles, genotype-positive patients with HCM showed substantially lower Dip-MBF compared with that of genotype-negative patients (1.7 ± 0.6 ml/min/g vs. 2.4 ± 1.2 ml/min/g; p < 0.02). A Dip-MBF <1.5 ml/min/g had 81% positive predictive value for genotype-positive status and implied a 3.5-fold independent increase in likelihood of carrying myofilament gene mutations (hazard ratio: 3.52; 95% confidence interval: 1.05 to 11.7; p = 0.04). At cardiac magnetic resonance imaging, the prevalence of late gadolinium enhancement was greater in genotype-positive patients (22 of 23 [96%] compared with 8 of 12 [67%] genotype-negative patients; p = 0.038). CONCLUSIONS: Patients with HCM with sarcomere myofilament mutations are characterized by more severe impairment of microvascular function and increased prevalence of myocardial fibrosis, compared with genotype-negative individuals. These findings suggest a direct link between sarcomere gene mutations and adverse remodeling of the microcirculation in HCM, accounting for the increased long-term prevalence of ventricular dysfunction and heart failure in genotype-positive patients.

Relationship between atrial fibrillation and blunted hyperemic myocardial blood flow in patients with hypertrophic cardiomyopathy.

BACKGROUND: Atrial fibrillation (AF) and coronary microvascular dysfunction (CMD) are common in hypertrophic cardiomyopathy (HCM), but whether they are associated is unclear. We assessed the relationship between AF and CMD in HCM. METHODS AND RESULTS: Global hyperemic myocardial blood flow (hMBF) was measured in 95 HCM patients (16 with, 79 without paroxysmal or chronic AF) by N-13 ammonia positron emission tomography (PET) after dipyridamole infusion. AF patients were older (50.5 +/- 13.4 vs. 38.7 +/- 14.9 years, P < .0005), had larger left atrial diameter (49.8 +/- 7.4 vs 38.6 +/- 5.7 mm, P < .00001), and left ventricular end-systolic diameter (30.4 +/- 6.7 vs 25.5 +/- 5.3 mm, P < .005) compared with those in stable sinus rhythm. In patients with AF, hMBF was significantly lower (1.23 +/- 0.44 vs 1.87 +/- 0.90 mL/min/g, P < 0.0001). In multivariate logistic regression analysis, hMBF, left atrial diameter, and age were independently associated with AF (P < .05 for all). CONCLUSIONS: HCM patients with paroxysmal or chronic AF have lower hMBF than those in stable sinus rhythm. The association between CMD and AF is independent of other known predictors of AF, suggesting a causal link between these two features.

Microvascular dysfunction, myocardial ischemia, and progression to heart failure in patients with hypertrophic cardiomyopathy.

Microvascular dysfunction can be demonstrated in most patients with hypertrophic cardiomyopathy (HCM), both in the hypertrophied and nonhypertrophied myocardial walls, mostly due to intimal and medial hyperplasia of the intramural coronary arteries and subsequent lumen reduction. As a consequence, regional myocardial ischemia may be triggered by exercise, increased heart rate, or arrhythmias, in areas which are unable to increase myocardial blood flow. In patients with HCM, microvascular dysfunction leading to severe myocardial hypoperfusion during maximal hyperemia represents a strong predictor of unfavorable outcome, left ventricular remodeling with progressive wall thinning, left ventricular dysfunction, and heart failure. Accurate quantitative assessment of microvascular dysfunction and myocardial ischemia is not easily feasible in clinical practice. Although signs of inducible myocardial ischemia may be detected by electrocardiogram, echocardiography, or myocardial scintigraphy, the vasodilator response to dipyridamole by positron emission tomography is considered the method of choice for the assessment of maximal regional and global flow. Cardiac magnetic resonance provides further information, by late gadolinium enhancement (LGE), which may show areas where replacement fibrosis has occurred following microvascular ischemia and focal necrosis. LGE areas colocalize with severe regional microvascular dysfunction, are associated with increased prevalence of ventricular arrhythmias, and show more extensive distribution in the late stages of the disease, when heart failure is the dominant feature. The present review aims to provide a concise overview of the available evidence of microvascular dysfunction and ischemia eventually leading to disease progression and heart failure in HCM patients.

Assessment of the influence of atrial fibrillation on gated SPECT perfusion data by comparison with simultaneously acquired nongated SPECT data.

UNLABELLED: The impact of arrhythmias on the evaluation of perfusion data from myocardial gated SPECT has been assessed by comparing arrhythmic patients with nonarrhythmic patients or by simulating rhythm disturbances. Whether gating-related artifacts may have a clinically relevant influence on the evaluation of perfusion in atrial fibrillation (AF) patients is still uncertain. Recently, collection of nongated and gated datasets during the same SPECT acquisition has become possible. The aim of this study was to examine the difference in myocardial perfusion between simultaneously acquired gated and nongated SPECT data in AF patients. METHODS: In 44 consecutive AF patients who underwent myocardial perfusion SPECT for standard clinical indications, both a gated and a nongated study were simultaneously acquired. Perfusion was estimated in a masked manner on a 20-segment model using an established scoring scheme. RESULTS: Agreement was good between the gated and nongated perfusion scores on a segment basis; the agreement for resting scores was the highest, with those for stress and difference scores being lower (Spearman rho = 0.82, 0.74, and 0.55, respectively). On a patient basis, a similar trend was seen in summed resting scores (rho = 0.911), summed stress scores (rho = 0.779), and summed difference scores (rho = 0.596). When summed stress and summed difference data were grouped by severity class (normal, mild abnormality, moderate abnormality, and severe abnormality), agreement decreased from rho = 0.818, kappa = 0.639, for summed stress score to rho = 0.549, kappa = 0.367, for summed difference score. The severity class of inducible ischemia changed in 17 patients (39%) if a (summed) gated image was used instead of a standard nongated perfusion image. CONCLUSION: AF may have a clinically relevant impact on summed gated perfusion images, compared with images simultaneously obtained without gating in the same patients. Therefore, acquisition of a nongated SPECT study is mandatory for accurate assessment of myocardial perfusion in AF patients.

Spatial relationship between coronary microvascular dysfunction and delayed contrast enhancement in patients with hypertrophic cardiomyopathy.

UNLABELLED: To clarify the spatial relationship between coronary microvascular dysfunction and myocardial fibrosis in hypertrophic cardiomyopathy (HCM), we compared the measurement of hyperemic myocardial blood flow (hMBF) by PET with the extent of delayed contrast enhancement (DCE) detected by MRI. METHODS: In 34 patients with HCM, PET was performed using (13)N-labeled ammonia during hyperemia induced by intravenous dipyridamole. DCE and systolic thickening were assessed by MRI. Left ventricular myocardial segments were classified as with DCE, either transmural (DCE-T) or nontransmural (DCE-NT), and without DCE, either contiguous to DCE segments (NoDCE-C) or remote from them (NoDCE-R). RESULTS: In the group with DCE, hMBF was significantly lower than in the group without DCE (1.81 +/- 0.94 vs. 2.13 +/- 1.11 mL/min/g; P < 0.001). DCE-T segments had lower hMBF than did DCE-NT segments (1.43 +/- 0.52 vs. 1.91 +/- 1 mL/min/g, P < 0.001). Similarly, NoDCE-C segments had lower hMBF than did NoDCE-R (1.98 +/- 1.10 vs. 2.29 +/- 1.10 mL/min/g, P < 0.01) and had no significant difference from DCE-NT segments. Severe coronary microvascular dysfunction (hMBF in the lowest tertile of all segments) was more prevalent among NoDCE-C than NoDCE-R segments (33% vs. 24%, P < 0.05). Systolic thickening was inversely correlated with percentage transmurality of DCE (Spearman rho = -0.37, P < 0.0001) and directly correlated with hMBF (Spearman rho = 0.20, P < 0.0001). CONCLUSION: In myocardial segments exhibiting DCE, hMBF is reduced. DCE extent is inversely correlated and hMBF directly correlated with systolic thickening. In segments without DCE but contiguous to DCE areas, hMBF is significantly lower than in those remote from DCE and is similar to the value obtained in nontransmural DCE segments. These results suggest that increasing degrees of coronary microvascular dysfunction might play a causative role for myocardial fibrosis in HCM.

Estimate of myocardial salvage in late presentation acute myocardial infarction by comparing functional and perfusion abnormalities in predischarge gated SPECT.

PURPOSE: We hypothesized that, because of persistent stunning, the extent of post-treatment functional abnormalities detected using gated single-photon emission computed tomography (SPECT) could be representative of the initial risk area in acute myocardial infarction (AMI) treated by reperfusion therapy. MATERIALS AND METHODS: In 48 AMI patients, we acquired two 99mTc-sestamibi gated SPECT studies (at admission with tracer injection before treatment and at discharge 5 to 10 days later). We assessed the myocardial salvage defined by the admission minus predischarge summed rest score, and we compared it with the value obtained by subtracting the extent of perfusion defect from the extent of wall motion or wall thickening abnormalities in predischarge gated SPECT. Myocardial salvage was expressed as salvage index (salvaged myocardium divided by initial risk area). RESULTS: There was a good correlation between summed rest score salvage index and wall motion (Spearman's rho = 0.754, p < 0.0001) or wall thickening salvage index (Spearman's rho = 0.798, p < 0.0001). The wall thickening salvage index was able to classify correctly the patients that had a summed rest score salvage index > or = 0.10 with 73% sensitivity, 88% specificity, and 83% accuracy. The wall motion salvage index was highly sensitive (91%) but poorly specific (13%, p < 0.002 vs wall thickening salvage index) and less accurate (69%, p < 0.05 vs wall thickening salvage index). CONCLUSIONS: 99mTc-sestamibi gated SPECT allows assessing myocardial salvage using only post-treatment data. The salvage index derived using wall thickening as surrogate of admission perfusion defect correlates well with the salvage index measured by comparing pre- and post-treatment perfusion defects.

Influence of the postexercise acquisition delay on the detection of functional abnormalities in sestamibi-gated SPECT.

BACKGROUND: Gated single photon emission computed tomography (SPECT) identifies functional changes produced by ischemia, but the influence of acquisition delay on their detection is not established. METHODS AND RESULTS: In 80 patients with known or suspected coronary artery disease, gated SPECT was acquired twice: first, less than 30 minutes after peak exercise (stress 1), and second, more than 45 minutes after peak exercise (stress 2). End-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF) were compared with perfusion. The relationship between the DeltaEF (stress EF - resting EF) and the summed difference score (SDS) was -0.443 (P < .0001) for stress 1 and -0.416 (P < .0001) for stress 2. In stress 1, EF increased in patients without inducible ischemia (SDS = 0) (57% +/- 10% vs 54% +/- 9% at rest, P < .02) and decreased in those with an SDS of 1 or greater (53% +/- 10.8% vs 55% +/- 9.6% at rest, P < .05). In stress 2, EF was unchanged in patients without ischemia (55.8% +/- 9.7%, P = .06) and decreased in the other patients (52.8% +/- 10.2%, P < .01). In patients without ischemia, both the EDV and ESV decreased significantly in stress 1 and were unchanged in stress 2. In patients with an SDS of 1 or greater, the EDV remained unchanged and the ESV minimally decreased in stress 1, whereas both volumes clearly and significantly increased in stress 2. CONCLUSIONS: The early acquisition of postexercise gated SPECT is slightly more effective in detecting ischemia-related functional changes; however, a delayed acquisition within 60 minutes still permits the detection of functional abnormalities in most patients.

A direct ROI quantification method for inherent PVE correction: accuracy assessment in striatal SPECT measurements.

PURPOSE: The clinical potential of striatal imaging with dopamine transporter (DAT) SPECT tracers is hampered by the limited capability to recover activity concentration ratios due to partial volume effects (PVE). We evaluated the accuracy of a least squares method that allows retrieval of activity in regions of interest directly from projections (LS-ROI). METHODS: An Alderson striatal phantom was filled with striatal to background ratios of 6:1, 9:1 and 28:1; the striatal and background ROIs were drawn on a coregistered X-ray CT of the phantom. The activity ratios of these ROIs were derived both with the LS-ROI method and with conventional SPECT EM reconstruction (EM-SPECT). Moreover, the two methods were compared in seven patients with motor symptoms who were examined with N-3-fluoropropyl-2-beta-carboxymethoxy-3-beta-(4-iodophenyl) (FP-CIT) SPECT, calculating the binding potential (BP). RESULTS: In the phantom study, the activity ratios obtained with EM-SPECT were 3.5, 5.3 and 17.0, respectively, whereas the LS-ROI method resulted in ratios of 6.2, 9.0 and 27.3, respectively. With the LS-ROI method, the BP in the seven patients was approximately 60% higher than with EM-SPECT; a linear correlation between the LS-ROI and the EM estimates was found (r=0.98, p=0.03). CONCLUSION: The LS-ROI PVE correction capability is mainly due to the fact that the ill-conditioning of the LS-ROI approach is lower than that of the EM-SPECT one. The LS-ROI seems to be feasible and accurate in the examination of the dopaminergic system. This approach can be fruitful in monitoring of disease progression and in clinical trials of dopaminergic drugs.

ST-segment analysis to predict infarct size and functional outcome in acute myocardial infarction treated with primary coronary intervention and adjunctive abciximab therapy.

ST-segment resolution is used to classify the response to reperfusion therapy in acute myocardial infarction, but the possibility to predict outcome in individual patients is unclear, particularly in the setting of primary percutaneous coronary intervention (PCI) and abciximab therapy. We studied 213 patients who underwent successful revascularization with PCI. Maximal ST-segment elevation was measured before and 30 minutes after PCI. Patient outcome was defined on the basis of infarct size and left ventricular ejection fraction (EF) as derived from gated single-photon emission computed tomography that was acquired 1 month after infarction. Patients who had > or =50% ST resolution showed a smaller infarct (15.1 +/- 13.6% vs 19.9 +/- 15.7%, p < 0.05) but not a higher left ventricular EF (48.7 +/- 12.3% vs 45.2 +/- 11.8%) than did patients who had <50% resolution. According to cluster analysis of infarct size and left ventricular EF, 132 patients had favorable outcome (central values: infarct size 7.5%, left ventricular EF 55%) and 81 did not (central values: infarct size 30%, left ventricular EF 36%). Using receiver-operating characteristic curve analysis, the optimal ST-resolution cutoff was >60%, with 77% sensitivity and 51% specificity for predicting favorable outcome. ST-segment elevation < or =4.5 mV before PCI was 80% sensitive and 48% specific, and ST-segment elevation < or =1 mV after PCI was 74% sensitive and 60% specific for predicting favorable outcome. In conclusion, in the setting of primary PCI and abciximab therapy, ST-segment elevation resolution requires a high threshold (>60%) to effectively classify patients; the capability of ST-segment analysis to predict patient outcome is limited, with ST-segment elevation after PCI showing the best compromise between sensitivity and specificity.